Allow about 20 mins

To help students unpick the difference between force, energy and power you can do the following activity.

Pick one student who will be happy to demonstrate doing some bicep curls in front of the others. Using a moderate weight, they perform a number of reps.  As they do this several data points are recorded: mass lifted, vertical distance moved, the total number of reps, the time taken (other students can help to record this data).

You can watch a beginner’s guide to bicep curls here.

In the following video Alan goes through the motions.

This is all recorded in a table (here is some sample data, which makes it clear what is measured and what is calculated):

Once the students have watched someone do an example as a whole class, they can then perform it themselves in small groups. One of the exercises they can perform is step-ups onto a step – where the weight used is their entire body weight.

Once students have performed a range of different exercises they can make sensible comparisons:

• are you more powerful with certain muscles? 
• how do your legs compare to your arms? 
• what difference does increasing the mass you are using do to your total work done, your power and the number of reps you can do? 
• your body uses many times more energy doing a set of reps than we have calculated – why is that?